Evaporator for refrigerating machines



June 9, 1936. 1.. w. ATCHISON EVAPORATOR FOR REFRIGERATING MACHINES Filed Nov. 1

Inventor Leon 0rd W 'Aochison,

His Attorney.

Patented June 9, 1936 UNITED STATES 2,043,917 EVAPORA'IOR FOR REFRIGEBATING MACHINES Leonard W.

Atchison, Schenectady, N. Y.. al-

signor to General Electric Gompany, a corporation of New York Application November 1, 1934, Serial No. 750,977 20 Claims. (Cl. 62-126) My invention relates to flooded type evaporators for refrigerating machines.

Flooded evaporators are ordinarily provided with a header or other vapor separating chamber 5 and an extended liquid refrigerant circulatory passage, liquid vaporizable refrigerant being supplied to the evaporator from a compressor-com denser unit, or other refrigerant liquefying apparatus. The liquid refrigerant supplied to the evaporator is preferably injected into the circulatory' passage in order to set up a positive flow of refrigerant in a predetermined direction and to increase the velocity of circulation. The circulating liquid refrigerant is vaporized by the absorption of heat from articles contained in the compartment in which the evaporator is located. The passage communicates with the header in with the refrigerant, vaporized by the absorption of heat is separated from the remaining liquid refrigerant, the vaporized refrigerant being from the header.

It is an object of my invention to provide an improved arrangement for injecting liquid refrigerant in a flooded evaporator in such manner as 25 to obtain rapid circulation of liquid refrigerant through the passages of the evaporator and thereby obtain the maximum absorption of heat by the liquid refrigerant from the walls of the evaporator.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to the accompanying drawing in which Fig. 1 is a front elevation of a refrigerating machine having an evaporator embodying my invention; Fig. 2 is a perspective view partly in section of the evaporator shown in Fig. 1; Fig. 3 is a sectional view on the line 3--3 of the evaporator shown in Fig. 2, and Fig. 4 45 is a. fragmentary view. partly in section, of a modified form of equalizer conduit for the evaporator shown in Fig. 2.

Referring to the drawing, in Fig. l, I have shown a refrigerating machine including an evaporator embodying my invention. In this machine, a motor and compressor are arranged in an hermetically sealed casing lli. Gaseous refrigerant is compressed by the motor driven compressor in the casing Hi and is discharged into a condenser II where itis liquefied. The liquefied returned to the refrigerant liquefying apparatus refrigerant passage 3! refrigerant flows from the condenser l.l through a flow controlling float valve l2 into a liquid line l3 from which the liquid refrigerant is injected into an evaporator ll. The liquid refrigerant is vaporized in 'the evaporator by the absorption of heat and the vaporized refrigerant is returned to the compressor through the suction line Ila.

The evaporator It comprises two complementary sheet metal portions i5 and it. The inner smooth sheet i6 is provided with a pair of transverse indentations i1 and i8 adjacent the upper edges thereof, which cooperate with the complementary indentations l9 and 20 in the outer sheet i5 to form the cylindrical headers 2| and 22. The outer sheet I5 is also provided with a plurality of parallel indentations or corrugations 23 to 3 I, inclusive, which cooperate with the smooth sheet to form depending refrigerant circulatory passages connecting the headers 2i and 22 and communicating with the headers below the normal liquid levels therein. The inner smooth sheet i6 is made slightly larger than the outer sheet i5 and its longitudinal edges are folded over the adjacent edges of the sheet ii. The sheets if: and it are then welded or otherwise secured together along their peripheral edges and between the refrigerant passages formed therein. The welding may be in the form of a line weld or a series of spot welds, or the sheets may be brazed together or joined in some other manner, if desired. After having been secured together the sheets i5 and It are bent into a U-shape, as shown in the drawing. Inturned flanges 32 and 33 are provided at the top of the legs of the U to facilitate the mounting of the evaporator it in the cabinet 34 by screws or bolts passing through the holes 35 and 36 in the flanges 32 and 33 respectively. Articles to be frozen, such as trays of water, may conventiently be supported on the intermediate part of the sheet metal portions and within the compartment, thus formed by the evaporator ll.

Liquid vaporizable refrigerant is supplied to the evaporator it through the liquid line l3 which enters the evaporator through the side wall of the header 22, passes downwardly through the and terminates in a transverse flute 31 formed in the inner sheet l3. Liquid refrigerant is injected upwardly into the refrigerant circulatory passages from the refrigerant supply conduit l3. This arrangement for injecting liquid refrigerant into a plurality of refrigerant circulatory passage communicating with a header of an evaporator is not my invention, but is the invention of Christian Steenstrup and is described and claimed in his copending application, Serial No. 658,321, filed February 24, 1933, and assigned to General Electric Company, the assignee of my present invention.

In accordance with my invention, the evaporator is provided with passages for recirculating liquid refrigerant from one header to the other in order, that all of the liquid refrigerant may be most efficiently utilized for absorbing heat from articles to be cooled. I prefer to inject the liquid refrigerant into a centrally located group of refrigerant passages, the recirculating passages being located on each side. thereof, as shown in the illustrative form of my invention, in order that the length of the circulatory path of the liquid refrigerant through the headersmay be reduced to a minimum. In the form of my invention, which is illustrated in the drawing, liquid refrigerant is injected through the refrigerant circulatory passages 25, 26, 21, 29, and 29, from the holes 38 in the upper side of the refrigerant supply conduit l3, as indicated by the arrows in Fig. 2. The liquid refrigerant thus injected passes upwardly into the header 22, and as it circulates through these passages 25 to 29 inclusive, it absorbs heat from articles contained in the cabinet 34 in which the evaporator is located and is partially vaporized by such absorption of heat. The vaporized refrigerant separates from the liquid refrigerant in the header 22 and the liquid refrigerant is recirculated through the refrigerant circulatory passages 23, 24, 30, and 3|. The liquid refrigerant from the header 22 passes downwardly through these passages as indicated by the arrowsin Fig. 2 and enters the header 2|. The liquid refrigerant, passing through the passages 23, 24, 30, and 3| is also partially vaporized by the absorption of heat and the vaporized refrigerant is collected in the header 2 The liquid refrigerant, remaining in the header 2|, flows downwardly through the passages 25 to 29, inclusive, back to the injection point where it is entrained by fresh liquid refrigerant entering the evaporator from the liquid supply conduit l3. The headers 2| and '22 are normally maintained about half full of liquid refrigerant, the vaporized refrigerant being collected in the upper parts of the headers. The vaporized refrigerant collected in the header 22 passes through an equalizing conduit 39 to the header 2|. In the evaporator shown in Fig. 2, the equalizing conduit 39 is connected to the headers 2| and 22 above the normal liquid levels therein and serves simply as a pressure equalizer and to convey the vaporized re frigerant.

I have found that when a refrigerant, such as methyl formate is used as a refrigerant, in an evaporator of the type described, in which the difference in density between the lubricating oil and the refrigerant is small and in which the lubricating oil is broken up into small globules by the agitation caused by the injectors, the oil will circulate almost as a part of the refrigerant body until it reaches a sufllcientiy quiet place to permit separation therefrom by gravity. Thus it will be seen that the evaporator shown in Fig. 2 is particularly adapted for use with refrigerants of this type, as it is not necessary that the equalizing conduit 39 serve to convey oilfrom the header 22 to the header 2| since it will be carried thereto by the liquid refrigerant.

A suction line |4a is connected to the header 2| rather than to the header 22 as the liquid refrigerant in the header 2| is agitated to a lesser extent than that in the header 22, since the injectors aremore remote therefrom, and it is desirable to locate the suction line connection in a quiet zone in order to guard against the return of the compressor and also to in order that oil may be skimmed oil the surface of the liquid refrigerant in the header. 2| and returned to the compressor in casing l0 through An oil separatiodcup 4 9 isend of the suction line |4a the suction line a, these holes being placed high enough on the sides of the cup 49 to preclude the entrance therethrough 'of liquid refrigerant.

more particularly. adapted for use with refrigerants, such as sulphur dioxide, which have a density which differs materially from that of the lubricating oil used therewith.- As shown in Fig. 4, the headers 2|a and 220 are connected by an equalizing conduit 50 communicating with these header 2| by the liquid refrigerant circulating through the equalizing conduit 50 and may be returned to the compressor in the casing -||l through the suction line |4a.

While I have shown a particular embodiment of shown and described,

pended claims to cover all modifications within in forproviding a path for the in connection with a compression u e. b

portions at least one of said sheet metal portions having an indentation thereinforming a header, a plurality of refrigerant circulatory passages formed between said sheet metal portions and communicating with said header below the normal liquid level therein, said passages communicating with eaclr other remote from said header,

and means for injecting liquid refrigerant into only part of the total number of said refrigerant passages and remote from said header, the remainder of said refrigerant passages providing a path for the recirculation of liquid refrigerant from said header.

3. A flooded evaporator for refrigerating machines comprising a pair of headers, means extending between said headers providing a horizontal surface for supporting articles to be cooled, said means including a plurality of refrigerant circulatory passages communicating with said headers below the normal liquid levels therein, and means injecting liquid refrigerant into only a part of the total number of said passages in portions thereof remote from said headers for producing circulation of liquid refrigerant from one of said headers to the other of said headers, the remainder of said refrigerant passages providing a path for the recirculation of liquid refrigerant from said other header to said 4. An evaporator of the flooded type for refrigerating machines comprising complementary sheet metal portions, at least one of said sheet metal portions having indentations therein forming headers adjacent the opposite edges of said sheet metal portions, the intermediate part of said sheet metal portions providing a support for articles to be cooled, a plurality of refrigerant circulatory passages formed between said sheet metal portions and communicating with said headers below the normal liquid levels, therein, and means injecting liquid refrigerant into only a part of the total number of said passages in portions thereof remote from said headers for producing circulation of liquid refrigerant from one of said headers to the other of said headers, the remainder of said refrigerant passages providing a path for the recirculation of liquid refrigerant from said other header to said one header.

5. A flooded evaporator for refrigerating machines comprising complementary U-shaped sheet metal portions, at least one of said sheet metal portions having indentations therein forming a a plurality of depending refrigerant circulatory )assages communicating with said headers below the normal liquid levels therein, and means injecting liquid refrigerant into only a part of the total number of said passages remote from said headers for producing circulation of liquid refrigerant from one of said headers to the other of said headers, the remainder of said refrigerant passages providing a path for the recirculation of liquid refigerant from said other header to said one header.

6. A flooded evaporator for refrigerating machines comprising complementary U-shaped sheet metal portions, at least one of said sheet metal portions having indentations therein forming a header adjacent the top of each leg of the U and a plurality of depending refrigerant circulatory passages communicating with said headers below the normal liquid levels therein, a transverse flute in one of said sheet metal portions, and means injecting liquid refrigerant into only a part of the total number of said passages remote from said headers including a refrigerant conduit located in said transverse flute, the remainder of said reheader adjacent the top of each leg of the U and frigerant passages providing a path for the recirculation of liquid refrigerant from one of said headers to the other.

7. A flooded evaporator for refrigerating machines including a header, means for circulating liquid refrigerant supplied to said evaporator, said means including a plurality of refrigerant circulatory passages communicating with said header below the normal liquid level therein and communicating with each other at a point remote from said header, and means for injecting liquid refrigerant into a central group of said refrigerant passages remote from said header, the remainder of said refrigerant passages providing a path for the recirculation of liquid refrigerant from said header.

8. A flooded evaporator for refrigerating machines including a pair of headers, means for circulating liquid refrigerant supplied to said evaporator, said means including a plurality of depending refrigerant circulatory passages opening into said headers below the normal liquid levels therein and means for injecting liquid refrigerant, into a centrally located group of said passages at points remote from said headers, the remainder of said passages providing a path for the recirculation of liquid refrigerant from one of said headers to the other.

9. A flooded evaporator for refrigerating machines including a pair of headers, means for circulating liquid refrigerant supplied to said evaporator, said means including a plurality of refrigerant circulatory passages communicating with said headers below the normal liquid levels liquid refrigerant therein, means for injecting into a part of said passages at points below one of said headers, the remainder of said passages providing a path for the recirculation of liquid refrigerant from one of said headers to the other, and means for removing vaporized refrigerant from the one of said headers most remote from said first mentioned means.

10. A flooded evaporator for refrigerating machines including a pair of headers, means for circulating liquid refrigerant supplied to said evaporator, said means including a plurality of refrigerant circulatory passages communicating with said headers below the normal liquid levels therein, means for injecting liquid refrigerent into a centrally located group of said passages at points below one of said headers, the remainder of said passages providing a path for the recirculation of liquid refrigerant from one of said headers to the other, and means for removing vaporized refrigerant from the one of said headers most remote from said first mentioned means.

11. A flooded evaporator for refrigerating machines comprising complementary U -shaped sheet metal portions, at least one of said sheet metal portions having indentations therein forming a header adjacent to the top of each leg of the U, a plurality of depending refrigerant circulatory passages formed between said sheet metal portions and communicating with said headers below the normal liquid level therein, means for injecting liquid refrigerant upwardly into part of said passages at a point below one of said headers, the remainder of said passages providing a path for the recirculation of liquid refrigerant from said one header to the other of said headers, and means for removing vaporized refrigerant from said other header.

12. A flooded evaporator for refrigerating machines comprising complementary U-shaped sheet metal portions, at least one of said sheet metal portions having indentations therein forming a header adjacent the top of each leg of the U, a plurality of depending refrigerant circulatory passages formed between said sheet metal portions and communicating with said headers below the normal liquid level therein, a transverse flute in one wall of said U-shaped evaporator, means for injecting liquid refrigerant into a part of said passages including a refrigerant conduit located in said transverse flute, the remainder of said passages providing a path for the recirculation of liquid refrigerant from the header above said transverse flute to the other of said headers, and means for removing vaporized refrigerant from said other header.

13. A flooded evaporator for refrigerating machines comprising complementary U-shaped sheet metal portions, at least one of said sheet metal portions having indentations therein forming a header adjacent the top of each leg of the U, a plurality of depending refrigerant circulatory passages formed between said sheet metal portions and communicating with said headers below the normal liquid level therein, a transverse flute on one wall of said U-shaped evaporator, means for injecting liquid refrigerant upwardly in a centrally located group of said passages and into one of said headers, the remainder of said passages providing a path for the recirculation of liquid refrigerant from said one header to the other of said headers, and means for removing vaporized refrigerant from said other header.

14. A flooded evaporator for refrigerating machines comprising complementary U-shaped sheet metal portions, at least one of said sheet metal portions having indentations therein forming a header adjacent the top of each leg of the U, a plurality of depending refrigerant circulatory passages formed between said sheet metal portions and communicating with said headers below the normal liquid levels therein, and means for injecting liquid refrigerant into a part of said passages including a refrigerant conduit entering the wall of one of said headers passing downwardly through one of said refrigerant passages to a point remote from said last mentioned header, the remainder of said refrigerant passages providing a path for the recirculation of liquid refrigerant from one of said headers to the other.

15. A flooded evaporator for refrigerating machines comprising complementary U-shaped sheet metal portions, at least one of said sheet metal portions having indentations therein forming a header adjacent the top of each leg of the U, a plurality of depending refrigerant circulatory passages formed between said sheet metal portions and communicating with said headers below the normal liquid levels therein, a transverse flute on one wall of said U-shaped evaporator, means for injecting liquid refrigerant upwardly into a centrally located group of said passages including a refrigerant conduit entering said evaporator through a wall of the headerabove said transverse flute passing downwardly through one of said refrigerant passages and through said transverse flute, the remainder of said refrigerant passages providing a path for the recirculation of liquid refrigerant from the header above said transverse flute to the other of said headers.

16. A flooded evaporator for refrigerating machines comprising complementary U-shaped sheet metal portions, at least one of said sheet metal portions having indentations therein forming a header adjacent the top of each leg of the U, a plurality of depending refrigerant circulatory passages formed between said sheet metal portions and communicating with said headers below the normal liquid levels therein, a transverse flute on one wall of said U-shaped evaporator, means for injecting liquid refrigerant upwardly into a 5 centrally located group of said passages including a refrigerant conduit entering said evaporator through a wall of the header above said transverse flute passing downwardly throughone of said refrigerant passages and through said trans- 10 verse flute, the remainder of said refrigerant passages providing a path for the recirculation of liquid refrigerant from the header above said transverse flute to the other of said headers, and means for removing vaporized refrigerant from 15 said other header.

17. A flooded evaporator for refrigerating machines including a pair of headers, means for circulating liquid refrigerant supplied to said evaporator, said means including a plurality of de- 20 pending refrigerant circulatory passages communicating with said headers below the normal liquid levels therein, a pressure equalizer tube connecting said headers above the normal liquid levels therein, and means for injecting liquid re- 25 frigerant into a part of said passages remote from said headers, the remainder of said passages providing a path for the recirculation of liquid refrigerant from one of said headers to the other.

18. A flooded evaporator for refrigerating ma- 30 chines including a header, means for circulating liquid refrigerant supplied to said evaporator, said means including a refrigerant circulatory passage communicating with said header, a suction line extending within said header for the removal of 35 vaporized refrigerant therefrom, a cup surrounding the end of said suction line within saidheader, said cup being provided with'an aperture in the side thereof to provide for the admission of lubricant to said cup from the surface of liquid re- 40 frigerant in said header, and means arranged in said header and obstructing the said liquid refrigerant in said header.

19. A flooded evaporator for refrigerating machines including a header, means for circulating frigerant in said header past said cup for provid- 60 on each side of said cup in spaced relation thereto. 65

20. A flooded evaporator for refrigerating maerant into a plurality of said passages for circulating liquid refrigerant away from said header through a group 01' said passages and for returning said liquid refrigerant to said header through the remainder of said passages, means including a pair of baiiies spaced apart and arranged within said header for providing a quiet zone of liquid within said header, the refrigerant circulatory passages entering said header between said baifles being in said group circulating reirig erant away from said header, and a suction line extending within said header between said baflies for the removal of vaporized refrigerant from said evaporator. I

LEONARD W. ATCHISON. 

